Fast Determination of Induction Period of Motor Gasoline Using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy
LIU Ya-fei1, YUAN Hong-fu1*，SONG Chun-feng1, XIE Jin-chun1, LI Xiao-yu1, YAN De-lin2
1. College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China 2. Sinopec Beijing Oil Products Company, Beijing 100023, China
Abstract：A new method is proposed for the fast determination of the induction period of gasoline using Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR). A dedicated analysis system with the function of spectral measurement, data processing, display and storage was designed and integrated using a Fourier transform infrared spectrometer module and chemometric software. The sample presentation accessory designed which has advantages of constant optical path, convenient sample injection and cleaning is composed of a nine times reflection attenuated total reflectance (ATR) crystal of zinc selenide (ZnSe) coated with a diamond film and a stainless steel lid with sealing device. The influence of spectral scanning number and repeated sample loading times on the spectral signal-to-noise ratio was studied. The optimum spectral scanning number is 15 times and the optimum sample loading number is 4 times. Sixty four different gasoline samples were collected from the Beijing-Tianjin area and the induction period values were determined as reference data by standard method GB/T 8018—87. The infrared spectra of these samples were collected in the operating condition mentioned above using the dedicated fast analysis system. Spectra were pretreated using mean centering and 1st derivative to reduce the influence of spectral noise and baseline shift. A PLS calibration model for the induction period was established by correlating the known induction period values of the samples with their spectra. The correlation coefficient (R2), standard error of calibration (SEC) and standard error of prediction (SEP) of the model are 0.897, 68.3 and 91.9 minutes, respectively. The relative deviation of the model for gasoline induction period prediction is less than 5%, which meets the requirements of repeatability tolerance in GB method. The new method is simple and fast. It takes no more than 3 minutes to detect one sample. Therefore, the method is feasible for implementing fast determination of gasoline induction period, and of a positive meaning in the evaluation of fuel quality.
Key words：ATR-FTIR;Gasoline;Oxidation stability;Induction period
刘亚飞1，袁洪福1*，宋春风1，谢锦春1，李效玉1，闫德林2 . 傅里叶变换衰减全反射红外光谱测定车用汽油诱导期方法研究 [J]. 光谱学与光谱分析, 2014, 34(11): 2929-2933.
LIU Ya-fei1, YUAN Hong-fu1*，SONG Chun-feng1, XIE Jin-chun1, LI Xiao-yu1, YAN De-lin2 . Fast Determination of Induction Period of Motor Gasoline Using Fourier Transform Attenuated Total Reflection Infrared Spectroscopy . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2014, 34(11): 2929-2933.
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